BRASILA, Brazil–With Cristiano Ronaldo and Luis Suárez long gone, and Neymar out with a fractured vertebra, there is just one otherworldly superstar left in the World Cup.

On Saturday, in the capital of his nation's top rival but in front of tens of thousands of screaming countrymen, Lionel Messi showed he has every intention of filling the vacuum left by the few peers he has in this sport, as Argentina beat Belgium 1-0, slaying the last of the World Cup's fashionable dark horses.

Messi didn't score. The winning strike came just eight minutes into the game, a whirling volley rocket off the foot of Gonzalo Higuain, who got on top of a loose ball 17 yards from the goal on the right side of the penalty area and buried it inside the far post.

But goals are rarely just a product of the player who delivers it into the net. This one began several seconds before, with Messi 10 yards across midfield, dancing on the ball, feinting right and left, drawing Belgium's midfielders and the attention of its defense, then sending the ball up the wing to Angel Di Maria. His shot from 20 yards deflected to an unmarked Higuain. The ball was passed Belgium goalkeeper Thibault Courtois, perhaps the best in the world at his position, before he could even move.

A half-hour into the game, Messi hit a perfect 40-yard through ball from his own half that settled perfectly onto Di Maria's sprinting feet. A minute later he took out Belgium defender Jon Vertronghen with the sort of open field trip that a lot of players barely 5-foot-7 might be too timid to commit.

Just before halftime he used his seemingly glue-covered boots to collect a sharp cross just outside the penalty area. Three Belgians stabbed at it hopelessly, until one of them had to step on Messi's foot to stop him from getting off a shot from one of his favorite spots.

The victory put Argentina in a World Cup semifinal for the first time in 24 years, back when Diego Maradona led the team.

Now, this is Messi's team, and Argentina coach Alejandro Sabella could not have been more effusive in his praise.

"It is not only about scoring goals," Sabella said after the match. "It is having the ball and bringing together three opponents." Sabella said every move Messi makes is "a sign of hope for us," that a player who receives the ball as Messi does and so rarely gives it up "is water in the desert" for the team. "Today when it was dry he gave us that breath of fresh air every time he held on to the ball."

Marc Wilmots, Belgium's coach lauded Messi, too, noting the frustration he causes by never losing the ball, but he also said the referee favored the superstar too much, giving him the benefit of the doubt on nearly every call.

"I don't want to be a crybaby," said Wilmots, being something of a crybaby, "but every little call goes for Argentina." He said he wasn't not impressed with Argentina as a team, or with the how it played, delaying before throw-ins and doing whatever it could to disrupt Belgium's rhythm.

"It's just an ordinary team," Wilmots said of Argentina.

Against the U.S., Belgium looked like the classiest of teams. They dominated possession, cut through the American midfield and flew up the wings. Against Argentina, they morphed into something decidedly mid-table, unable to generate much of an attack or string together more than a few passes once they advanced passed the middle of the field.

Divock Origi, Belgium's blazing 19-year-old striker, was nearly invisible during the hour he was on the field. Eden Hazard one of the world's most dangerous midfielders, couldn't get the Red Devils attack moving and left the game after 75 minutes. The lethal Romelu Lukaku, whose late-game substitution won the game for Belgium against the U.S., had just one serious threat on the goal in stoppage time.

Belgium's best chance came early in the second half, as Marouane Fellaina got his head on a cross from Vertronghen six yards from the goal but put it over the cross bar. In fairness, Fellaini spent much of the afternoon following his assignment to hound Messi whenever he touched the ball in the middle of the field—the match's tallest player hovering over its shortest.

In the final minutes, Belgium began dumping the ball into Argentina's penalty area, but never could take advantage of the ensuing chaos.

The Belgians had caught the fancy of the sport's cognoscenti the past two years, when they went undefeated in qualifying. Indeed they are among the best young teams in Europe and should be dangerous in the Euro in two years.

But this World Cup of early upsets and surprises is quickly being taken over by the heavyweights. Brazil, Argentina and Germany have all punched their tickets to the semifinals. In Saturday's other match, the Netherlands defeated Costa Rica on penalty kicks to make it a sweep for soccer royalty.

Despite a slow start in this World Cup and needing a goal in the 118th minute to survive a round of 16 scare against Switzerland, Argentina is gaining confidence at the right time. So are its fans, tens of thousands of whom arrived in Brasilia clad in their blue-and-white striped jerseys and turned Estadio Nacional into their own choir room. While their heroes battled Belgium in the field, the Argentine faithful went at it with the thousands of yellow-clad Brazilians, who tried to drown out Argentina's anthems with their whistles and chants of "Neymar".

When this tournament began, a final between the two giants of South American soccer was the matchup so many wanted here in what seems like the perfect setting for it. That game now hinges on two semifinals set for next week.

It won't be Neymar vs. Messi. It may not even be Messi. But there is little doubt where the spotlight will be shining Wednesday in São Paulo, or whether the little superstar is ready to step into it in whatever way he decides to.

"We worked hard for this," Higuain said. "We have two matches in order to make a dream come true."

I am sure the Argentineans are very proud of their national
team. However, only three of the players
are actually from Argentina. The team make up is 7 players from Italy, 4 from Spain,
three are English, 3 from Argentina,
two from Portugal, 1 from Mexico, France,
Russia and Monaco.

@Bill Weronko You must be new to this sport. All players from Argentina are 100% argentine, born and raised. Like most of the soccer elite players, they are scattered around the most competitive leagues the world.

This copy is for your personal, non-commercial use only. Distribution and use of this material are governed by our Subscriber Agreement and by copyright law. For non-personal use or to order multiple copies, please contact Dow Jones Reprints at 1-800-843-0008 or visit www.djreprints.com.